Inspector Zenigata arrives at Devil's Head Island, so named for the two peaks that seemingly form devil horns, having heard Lupin has been seen there. He is met by Goroohachi, the patrol officer of the island who is to escort the detective around. However, he proves clumsy and rather inept at his job. Zenigata sends him out anyway to search for word on Lupin.

The master thief himself, along with Fujiko, are resting on a nearby boat. Fujiko explains she has asked Lupin here to help her find a legendary treasure. Centuries ago, two warring families fought their final battle in the harbor of the island, leading to both of their ships sinking. The ship of the Heiki clan was supposedly filled with gold and other treasures. Lupin agrees and the two start their investigation in the Forest of Disappearances; legend says that anyone who enters will be taken away in the mists by the ghosts of the Heike and never seen again. Sure enough, a heavy mist rolls in, and three masked samurai on horseback appear from nowhere. They grab Fujiko and fight off Lupin; further delayed by interference from Zenigata and his new assistant, he can only track Fujiko down to the shoreline.

He spots the samurai and her loaded onto a conspicuously modern boat, with other boats forming a heavy patrol around another nearby island with an ancient castle on it. Jigen and Goemon, suspecting Fujiko to be up to something as usual, have followed Lupin and reluctantly agree to help him rescue Fujiko. Conveniently, Jigen says he has just the device to let Lupin slip quietly across the water...

On the island itself, an old man, Gempaku, the oldest surviving member of the Heike clan, watches from a window atop the castle. Watching the samurai bring Fujiko, he goes down to a lab to tell Momotaro, his descendant, that another "specimen" is being brought to the castle. Momotaro is surrounded by mounted butterflies, but he also disturbingly has a woman's corpse on the table in front of him. It is quickly clear something is wrong with Momotaro; rather than being entranced by the women Gempaku has brought to the castle and using them to create heirs, he is killing them, stuffing them, and mounting them like his butterfly specimens! Gempaku looks despondently on as Momotaro takes up his net to catch his next "butterfly."

Back outside, Lupin has been fitted with specially self-propelled water skis. He ends up flipping over and using them upside-down; luckily, he has a small breathing apparatus in his pocket for such emergencies. Unspotted, he makes it to the base of the castle; before he climbs up the foundations, he takes a quick picture of one of the passing patrol boats.

In the castle, Fujiko has woken, horrified, to Momotaro and his butterfly net standing over her. As he chases her around, Gempaku implores him to stop. Momotaro knows that before he kills Fujiko, he is supposed to get her to "sit on an egg." Gempaku laments his descendant's stupidity and insanity.

Under the sea, Zenigata and Goroohachi have acquired an impressive submarine and are looking for a sign of Lupin. With the castle sighted through the periscope, Zenigata, going on a hunch, decides to search there next for Lupin.

Fujiko, meanwhile, has finally been cornered by Momotaro, who has traded his net for a scalpel. He has now decided he has to put the egg inside of Fujiko, and in order to do that, he must perform surgery. He calls for his instruments, much to Fujiko and Gempaku's horror, and a loyal samurai servant brings them. Momotaro orders the servant to inject Fujiko with a sedative, and is most surprised when the needle is poked into his butt instead. The masked servant is, naturally, Lupin in disguise. Alas, Lupin has no plan of escape yet, but he promises he'll use his head.

Gempaku, waiting outside, realizes that things have gone quiet, and then spots one of the castle servants tied up, who tells the Heike that Lupin stole his clothes. Gempaku bursts into the room to find the unconscious Momotaro and no sign of Fujiko or Lupin. He sounds the alarm, and Lupin and Fujiko are trapped by him and several archers. Luckily, Jigen and Goemon arrive to take care of the guards, and all four manage to escape, infuriating Gempaku.

The gang are finally cornered by the castle guards at one end and Zenigata and Goroohachi at the other. However, Goroohachi's traffic directing skills kick in and he lets them by, directing the gang one way and the guards another. He and Zenigata take off after Lupin; the guys notice, however, that Fujiko has gone missing. She has stumbled onto the entrance of an underground lair where a submarine is being kept. Entering, she finds the missing treasure stacked inside! Before she can celebrate and take the loot as her own, Momotaro catches up to her. Lupin manages to find her and incapacitates Momotaro with a well-thrown rock.

While Lupin forgives her for trying to double cross him after she kisses him, Jigen and Goemon investigate the sub and find it has no power. Lupin, as always, has a plan. Using the camera from earlier, he projects the picture of the boat he took onto the wall, affixes the image permanently with a special chemical, and has Goemon cut the steel to make a cutout of the boat. Outside, Gempaku has has men searching and keeping an eye out for the thieves; he is unaware that Lupin is not only escaping, he is towing the submarine filled with treasure via Jigen's motorized skis, and has affixed the cutout to the tower as a disguise. By the time Gempaku figures it out, the bombs that Jigen had earlier placed around the castle go off, causing it to collapse in flames. The debris destroys the guard boats, Zenigata and Goroohachi's own sub runs out of power, and Lupin and his gang make a safe retreat with their ill-gotten gains.

TV Tropes is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Permissions beyond the scope of this license may be available from thestaff@tvtropes.org. Privacy Policy